1. Field of the Invention
The present invention relates generally to apparatus and methods for non-destructively measuring the strength of a specimen, especially a rock specimen from a subterranean formation. More particularly, the present invention is directed toward a light-weight, portable device that directly measures rock strength without destroying the entire rock specimen.
2. Description of the Prior Art
Geologists, geophysicists, and engineers often need to quantitatively measure the strength of rocks making up a particular subterranean rock formation during activities such as well drilling and well completion. The rock strength will frequently dictate whether a well bore needs to be cased or whether the rock formation possesses the strength to avoid collapse.
Various methods exist for determining the strength of a rock specimen. However, these methods generally involve sending the specimen to a remote laboratory for testing. In the meanwhile, the professionals working in the field may have to cease or slow down operations until the testing is completed. Also, many conventional methods for determining rock strength involve applying shear and normal forces to the specimen to the point of specimen failure. As such methods result in the destruction of the specimen, there is no way to perform repeat testing on the same specimen.
Therefore, there exists a need for a portable device that can be used in the field to measure the strength of a rock specimen without destroying the specimen in case further testing is required.